Conventionally, as a sealing device for sealing an annular gap between a shaft and a housing rotating relative to each other, there is known a sealing device that includes an elastomeric seal having a seal lip in slidable contact with the surface of the shaft, and a support member supporting the inner peripheral surface side of the elastomeric seal. Such a sealing device adopts various methods in order to fix the elastomeric seal in a state in which the seal is positioned relative to the support member. For example, there is known a method in which the elastomeric seal is vulcanization-molded integrally with the support member after an adhesive is applied to the support member (see Patent Literatures 1 and 2). In addition, there is also known a method in which the support member and the like are fixed by fitting a metal adaptor in a state in which the support member and the elastomeric seal are attached to attachment positions (see Patent Literature 3). Further, there is also known a method in which the support member is held by the elastomeric seal (see Patent Literature 4).
However, in the case of the method which uses the adhesive, when the sealing device is disposed of, the adhesive becomes a load to the environment. In addition, in the case where the sealing device is used in the water, a problem arises in that the adhesive is peeled due to time degradation.
In the case of the method which uses the adaptor, the number of components is increased due to the adaptor itself and a step for fitting the adaptor is needed, and hence a problem arises in that cost is increased. In addition, in case the sealing device needs to be installed in a narrow space, it may not be possible to secure a space in which the adaptor is fitted in the first place.
In the case where the support member is held by the elastomeric seal, a seal lip tends to be deformed. Accordingly, at a time of installing the sealing device or when a pressure on the sealed liquid side becomes negative, a problem arises in that the seal lip is significantly deformed toward the sealed liquid side and a sealing function is deteriorated.